Recycling of electrochemical devices

Abstract

Recycling of an electrochemical energy storage device is provided. A remaining charge on the electrochemical energy storage device is determined. An impedance profile of the electrochemical energy storage device is determined for the remaining charge. The impedance profile includes an internal impedance of the electrochemical energy storage device at different charge levels from the remaining charge to a complete discharge. A variable discharge load is applied on the electrochemical energy storage device until the complete discharge. The variable discharge load varies with the internal impedance of the electrochemical energy storage device at the different charge levels.

What is claimed is: 
     
       1. A method of discharging an electrochemical energy storage device, the method comprising:
 determining a remaining charge on the electrochemical energy storage device; 
 determining an impedance profile of the electrochemical energy storage device for the remaining charge, wherein the impedance profile comprises an internal impedance of the electrochemical energy storage device at different charge levels from the remaining charge to a complete discharge, and wherein determining the impedance profile comprises determining the impedance profile using Electrochemical Impedance Spectroscopy (EIS) device; and 
 applying a variable discharge load on the electrochemical energy storage device until the complete discharge, wherein applying the variable discharge load comprises varying a discharge load based on variation in the internal impedance of the electrochemical energy storage device at the different charge levels, and wherein varying the discharge load comprises increasing or decreasing the discharge load with an increase or decrease in the internal impedance in the impedance profile. 
 
     
     
       2. The method of  claim 1 , further comprising:
 providing energy stored in the electrochemical energy storage device to an electrical grid. 
 
     
     
       3. The method of  claim 1 , further comprising:
 varying the variable discharge load based on a temperature of the electrochemical energy storage device. 
 
     
     
       4. The method of  claim 3 , wherein varying the variable discharge load based on the temperature of the electrochemical energy storage device comprises at least one of the following:
 increasing the variable discharge load when the temperature of the electrochemical energy storage device is below a first predetermined temperature; and 
 decreasing the variable discharge load when the temperature of the electrochemical energy storage device is above a second predetermined temperature. 
 
     
     
       5. The method of  claim 1 , wherein applying the variable discharge load on the electrochemical energy storage device comprises applying the variable discharge load having a same impedance value as that of the internal impedance the electrochemical energy storage device. 
     
     
       6. The method of  claim 1 , wherein determining the impedance profile of the electrochemical energy storage device for the remaining charge comprises performing a lookup in a database comprising a plurality of impedance profiles for different types of electrochemical energy storage devices. 
     
     
       7. The method of  claim 1 , wherein the electrochemical energy storage device comprises a rechargeable battery. 
     
     
       8. A system comprising:
 a memory storage; and 
 a processing unit coupled to the memory storage, wherein the processing unit is operative to:
 determine a remaining charge on the electrochemical energy storage device; 
 determine an impedance profile of the electrochemical energy storage device for the remaining charge, wherein the impedance profile comprises an internal impedance of the electrochemical energy storage device at different charge levels from the remaining charge to a complete discharge, and wherein the processing unit being operative to determine the impedance profile comprises the processing unit being operative to determine the impedance profile using Electrochemical Impedance Spectroscopy (EIS) device; and 
 apply a variable discharge load on the electrochemical energy storage device until the complete discharge, wherein the processing unit being operative to apply the variable discharge load comprises the processing unit being operative to vary a discharge load based on variation in the internal impedance of the electrochemical energy storage device at the different charge levels, and wherein the processing unit being operative to vary the discharge load comprises the processing unit being operative to increase or decrease the discharge load with an increase or decrease in the internal impedance in the impedance profile. 
 
 
     
     
       9. The system of  claim 8 , wherein the processing unit is further operative to:
 provide energy stored in the electrochemical energy storage device to an electrical grid. 
 
     
     
       10. The system of  claim 8 , wherein the processing unit is further operative to:
 vary the variable discharge load based on a temperature of the electrochemical energy storage device. 
 
     
     
       11. The system of  claim 10 , wherein the processing unit being operative to vary the variable discharge load based on the temperature of the electrochemical energy storage device comprises the processing unit being operative to at least one of the following:
 increase the variable discharge load when the temperature of the electrochemical energy storage device is below a first predetermined temperature; and 
 decrease the variable discharge load when the temperature of the electrochemical energy storage device is above a second predetermined temperature. 
 
     
     
       12. The system of  claim 8 , wherein the processing unit being operative to apply the variable discharge load on the electrochemical energy storage device comprises the processing unit being operative to apply the variable discharge load having a same impedance value as that of the internal impedance the electrochemical energy storage device. 
     
     
       13. The system of  claim 8 , wherein the processing unit being operative to determine the impedance profile of the electrochemical energy storage device for the remaining charge comprises the processing unit being operative to perform a lookup in a database comprising a plurality of impedance profiles for different types of electrochemical energy storage devices. 
     
     
       14. A computer-readable medium that stores a set of instructions which when executed perform a method comprising:
 determining a remaining charge on the electrochemical energy storage device; 
 determining an impedance profile of the electrochemical energy storage device for the remaining charge, wherein the impedance profile comprises an internal impedance of the electrochemical energy storage device at different charge levels from the remaining charge to a complete discharge, and wherein determining the impedance profile comprises determining the impedance profile using Electrochemical Impedance Spectroscopy (EIS) device; and 
 applying a variable discharge load on the electrochemical energy storage device until the complete discharge, wherein applying the variable discharge load comprises varying a discharge load based on variation in the internal impedance of the electrochemical energy storage device at the different charge levels, and wherein varying the discharge load comprises increasing or decreasing the discharge load with an increase or decrease in the internal impedance in the impedance profile. 
 
     
     
       15. The computer-readable medium of  claim 14 , further comprising:
 providing energy stored in the electrochemical energy storage device to an electrical grid. 
 
     
     
       16. The computer-readable medium of  claim 14 , further comprising:
 varying the variable discharge load based on a temperature of the electrochemical energy storage device. 
 
     
     
       17. The computer-readable medium of  claim 16 , wherein varying the variable discharge load based on the temperature of the electrochemical energy storage device comprises:
 decreasing the variable discharge load when the temperature of the electrochemical energy storage device is above a second predetermined temperature. 
 
     
     
       18. The computer-readable medium of  claim 16 , wherein varying the variable discharge load based on the temperature of the electrochemical energy storage device comprises:
 increasing the variable discharge load when the temperature of the electrochemical energy storage device is below a first predetermined temperature. 
 
     
     
       19. The computer-readable medium of  claim 14 , wherein determining the impedance profile of the electrochemical energy storage device for the remaining charge comprises performing a lookup in a database comprising a plurality of impedance profiles for different types of electrochemical energy storage devices. 
     
     
       20. The computer-readable medium of  claim 14 , wherein applying the variable discharge load on the electrochemical energy storage device comprises applying the variable discharge load having a same impedance value as that of the internal impedance the electrochemical energy storage device.